Poplar-Based Ethanol

Let’s Talk About POPLAR-BASED ETHANOL

Developing a cellulosic ethanol industry in the Pacific Northwest can increase energy security, build local economies, and reduce net greenhouse gas emissions and global warming potential.

ETHANOL IN THE NORTHWEST Ethanol, an alcohol fuel made by fermenting the In the PNW, poplar trees are a promising feedstock sugars in plant material, is an important piece of the for cellulosic ethanol. Poplars require relatively few nation’s clean fuel portfolio. Most of the ethanol inputs compared to other agricultural crops, and produced in the U.S. is made from corn grown in researchers are also working to develop methods for the Midwest. This ethanol is distributed across the growing poplar on marginal lands where the trees will country, and even the globe, to be blended with not compete with food crops. Poplar-based ethanol gasoline. also offers reduced net greenhouse gas emissions compared to gasoline and corn ethanol because the A new generation of ethanol, called cellulosic ethanol, trees require fewer energy inputs (from reduced tillage can be made from trees, perennial grasses, and and fertilizer use) and their large root systems store agricultural residues like corn stover or wheat straw. carbon in the soil. Because ethanol is one of the easiest and cheapest AHB’s industry partner, ZeaChem, has been working to biofuels to produce from these feedstocks, it can also fine-tune their process to make ethanol from poplar serve as a stepping stone for the production of other wood chips. ZeaChem plans to expand their production advanced biofuels that are equivalent to petroleum- to a 22.5 million gallons per year facility that will based gasoline, diesel, and jet fuel. produce cellulosic ethanol from locally-sourced poplar.

Advanced Hardwood Biofuels Northwest (AHB) is a program funded by the USDA National Institute of Food and Agriculture. AHB integrates research, education, and extension to develop a poplar-based biofuel and biochemical industry in the Pacific Northwest (PNW). hardwoodbiofuels.org October 2015 CONVERTING WOOD TO ETHANOL To make cellulosic ethanol, poplar wood chips are pre-treated with acid, steam, and enzymes to release sugars. The sugars can then be turned into ethanol in two ways.

1. YEAST FERMENTATION Yeast can ferment sugar directly to ethanol, which is the current method used to make corn ethanol. This process requires very little additional energy but produces lower yields compared to bacteria fermentation.

2. BACTERIA FERMENTATION Bacteria, similar to the type found in compost piles, ferment the sugars to acetic acid. The acidic acid is then converted to an intermediate product, ethyl acetate, which is reacted with hydrogen to make ethanol. The advantage of the bacterial pathway is an increased ethanol yield; Poplar chips at ZeaChem’s demonstration biorefinery in however, this process requires additional energy inputs, which could Boardman, OR. substantially affect the life cycle global warming potential of the process.

GGLOLOBALBAL W WARMIARMINNGG P OPOTENTIALTENTIAL When comparing the two pathways per unit GLOBAL WARMING POTENTIAL of energy produced, the yeast and bacteria 400400 400 fermentation pathways have an estimated GWP* that is 97% and 50% lower than the 300300 GWP of gasoline, respectively. However, 300 because the bacterial pathway achieves higher yields, less total land is needed to 200 200 produce a unit of ethanol. Therefore, when

200 EMITTED

EMITTED the GWP are compared per unit of land, the 100 EMITTED two pathways achieve similar reductions. 100 Combustion 100 Combustion CombustionMiscellaneous 0 Miscellaneous 0 MiscellaneousBiore nery Fuel Production 0 Biore nery Fuel Production Biore neryHydrogen FuelProduction Production -100 Hydrogen Production -100 HydrogenChemical Production Inputs -100 Chemical Inputs ChemicalFarming Inputs

Equivalence per MegaJoule of Energy -200 Farming

2 Equivalence per MegaJoule of Energy -200 Farming

2 Carbon in Biomass Equivalence per MegaJoule of Energy -200 Carbon in Biomass 2 Carbon in Biomass -300 EQUESTERED Avoided Production S -300 EQUESTERED Avoided Production S -300 EQUESTERED Avoided Production S Grams CO Net Emissions Grams CO -400 Net Emissions Grams CO Net Emissions -400 Poplar Poplar Corn Gasoline -400 Poplar Poplar Corn Gasoline Ethanol Ethanol Ethanol * The Global Warming Potential (GWP) is the EthanolPoplar EthanolPoplar EthanolCorn Gasoline Yeast Bacteria sum of greenhouse gas emissions expressed as EthanolYeast BacteriaEthanol Ethanol Fermentation Fermentation CO2 equivalence. FermentationYeast FermentationBacteria Fermentation Fermentation

For more information contact WSU Extension This project is supported by Agriculture and Food Research Initiative (425) 741-9922 or [email protected] or visit (AFRI) Competitive Grant no. 2011-68005-30407 from the USDA hardwoodbiofuels.org National Institute of Food and Agriculture (NIFA).